Chain tension adjusting apparatus



Oct. 1, 1968 M.J. ERISMAN CHAIN TENSION ADJUSTING APPARATUS 2Sheets-Sheet 1 Filed Oct. 3, 1966 5 2 3% 4 c 1 w 9 w w w, U m 333 33%1968 M. J. ERISMAN CHAIN TENSION ADJUSTING APPARATUS 2 Sheets-Sheet 2Filed Oct. 3, 1966 Edema .6 (ma-r2:

United States Patent 9 3,403,552 CHAIN TENSION ADJUSTING APPARATUSMaurice J. Erisman, Oak Park, Ill., assignor to F MC Corporation, acorporation of Delaware Filed Oct. 3, 1966, Ser. No. 583,727 8 Claims.(Cl. 73-443) This invention relates generally to traveling water screensand more particularly to an apparatus for measuring and selectivelyadjusting the tension in the chains which carry the moving screeningtrays.

Traveling water screens are installed in a substantially vertical mannerand form a part of a water intake system through which water flows priorto the point of treatment or usage. As the raw water passes through thescreening trays of the traveling water screen, the refuse in the wateris retained on the screening medium and is elevated for removal duringthe periodic operational cycles of the traveling water screen. As eachscreen tray is lifted out of the water the refuse is dislodged from thescreening medium and is carried away for disposal.

A traveling Water screen consists of a pair of transversely spacedvertically extending side frame members having a head shaft and a footshaft parallelly arranged and rotatably supported between the upper andlower end portions respectively of the side frame members. A pair oftransversely spaced endless chains are supported over a correspondingpair of spaced sprockets on the head shaft and extend verticallydownward therefrom to be trained around an associated pair of verticallyaligned foot sprockets on the foot shaft. A series of individualscreening trays are mounted between the chains and supported thereby ina manner to define an endless screening medium.

For the traveling water screen to function properly, the chains shouldbe operated and maintained at the tension value which will assure theproper operative engagement of the chains with their associatedsprockets. This is accomplished by rotatably supporting the oppositeends of the head shaft in bearing blocks which are sl'ideably moveableendwise along the side frame members. Each of the bearing blocks issupported by an elongatively adjustable structure so that the head shaftcan be adjusted to vary the distance between the head shaft and the footshaft, thereby adjusting the tension in the associated chains.

It is apparent that the chains must be sufficiently tensioned in orderto remain in the proper operative engagement with the foot sprockets,and yet must not be over tensioned to avoid interfering with the runningfreedom of the chains. If the chains are loose, undue wear will occur tothe chain and the chain guides, and should the chains be extremelyloose, damage to the traveling water screen will result from theaccumulation of excess slack in the chains where they are trained aroundthe foot sprockets. If, however, the chains are overtightened, theexcessive strains placed on the chains will cause undue wear to thechains, and will also interfere with the operational freedom of thescreening trays. It is therefore apparent that an apparatus which wouldpermit the accurate tensioning of the screen chains would alleviate theabovementioned problems and thereby extend the useful life of theassociated chains and sprockets.

As wear occurs in the chains and associated sprockets, the tension ofthe chains decreases accordingly. Reestablishment of the desired tensionis usually obtained by manipulation of an adjustable structure in amanner to tighten the chains until they appear to be in the properengagement with the foot sprockets while still maintaining a runningfreedom for the chains. Since the foot sprockets are normally submergeda substantial distance beneath the surface of the water, it isimpractical to rely on a visual inspection to determine when the chainsare 3,403,552 Patented Get. 1, 1968 properly seated with the footsprockets. It has therefore been the normal practice for the operatingpersonnel to apply their skill and judgment in adjusting the chains bythe method of trial and error, with the usual result being that thechains are not properly tensioned. Due to the expenses involved inreplacing the chains, and since the tension of the screen chains has adirect bearing on the useful life of the chains, it would be desirableto have a relatively inexpensive apparatus which would properly tensionthe chains to the selected value.

It is therefore a primary object of this invention to provide anapparatus for measuring and selectively adjusting the tension in achain.

Another object of this invention is to provide a portable chain tensionmeasuring and adjusting apparatus for simultaneously and uniformlyadjusting both of the chains supporting the screen trays in a travelingwater screen in a manner to obtain the same tension value in each of thechains.

Still another object of this invention is to provide a mechanism fortensioning the chains in a traveling water screen in a positive mannersuch that the proper tension value will be obtained each time the chainsare adjusted without requiring any special skills or judgment by theoperating personnel.

A further object of this invention is to provide an apparatus formeasuring and selectively adjusting the chains employed in a travelingwater screen which is simple to use, rugged and durable in construction,and which may be quickly and easily transported from one traveling waterscreen to another for tensioning the screen chains associated therewith.

These and other objects and advantages of the invention will be apparentduring the course of the following description.

In the accompanying drawings forming a part of this specification and inwhich like reference characters are employed to designate like partsthroughout the same;

FIGURE 1 is a fragmentary side elevational view illustrating the upperend portion of a traveling water screen;

FIGURE 2 is an enlarged fragmentary side elevational view illustratingthe placement of the invention relative to the traveling water screen;

FIGURE 3 is a fragmentary sectional view taken on line 33 of FIG. 2;

FIGURE 4 is a schematic view illustrating the fluid pressure controlsystem; and

FIGURE 5 is an enlarged fragmentary side elevational view illustratinganother mode of using the invention.

In the drawings, wherein for the purpose of illustration is. shown apreferred embodiment of the invention, and first particularly referringto FIGS. 1 through 3 inclusive, there is illustrated generally the upperend portion of a traveling water screen 11 having the side shown in thefigures and an opposite side which is identical in construction to theside shown and described hereinafter. Each side of the traveling waterscreen 11 includes a side frame 12 which is arranged to support theassociated end portion of a horizontal top plate 13 which transverselyextends between the opposed side frames. A horizontally extendingrectangular beam 14 consisting of a pair of spaced parallel side members15, a top member 16, and a bottom member 17 is mounted on the top plate13. A pair of spaced parallelly arranged vertical guide members 18 havetheir upper end portions secured to the side members 15 and extenddownwardly therefrom to be secured to the side frame 12. A bearing block19 is mounted for vertical slidable movement between the guide members18 in a manner to rotatably support the associated end portion of atransversely extending horizontal head shaft 20 which extends throughthe upper portion of the traveling water screen 11 and projects throughan opening 21 in the head shaft 20 adjacent the opposed side frames 12are the two head sprockets 22 which support the upper bights of theassociated pair of endless chains 23 trained thereover. The chains 23define a pair of transversely spaced vertically extending elongatedloops having their lower bights trained over a pair of axially spacedfoot sprockets, not shown, each of which is vertically aligned with itsassociated head sprocket 22. The foot sprockets are mounted on a footshaft, not shown, which is ver tically spaced from the head shaft 20 andis rotatably supported between the bottom end portions of the sideframes 12. A plurality of screen trays 24 are connected between thechains 23 in a manner to form an endless moveable screen structure.Movement is imparted to the chains 23 and their associated screen trays24 by rotatably driving the head shaft 20 in a conventional method whichdoes not form a part of this invention and therefore is not hereindescribed.

The tension in the chains 23 is selectably adjusted by means of raisingor lowering the head shaft 20 so as to vary the distance between thehead sprockets 22 and the associated foot sprockets, not shown, aroundwhich the chains are trained. To effect this adjustment the bearingblock 19 is supportedly mounted on the bottom end of a threaded take-upscrew 25 which extends vertically upwards therefrom between the guidemembers 18 and through aligned apertures in the top plate 13 and therectangular beam 14. The upper end of the take-up screw 25 is fittedwith a capstan nut 26 and a Washer 27 which rests on the top member 16such that the rotation of the capstan nut 26 will serve to either raiseor lower both the bearing block 19 and the associated end of the headshaft 20, depending upon the direction of rotation of the capstan nut. Ahorizontally arranged rectangular lifting plate 28 having an aperturedintegral boss 29 is supported on the upper end portion of the take-upscrew 25 in a position parallel to and intermediate the top member 16and bottom member 17 of the beam 14, and is secured in a selectableposition by being clamped between the nuts 33 and 34 which are fittedonto the take-up screw immediately above and below the lifting plate. Itwill be understood, of course, that there is an identical chain take-upmechanism disposed on the opposite side of the traveling water screen11, and that only the mechanism on one side is illustrated in thefigures which accompany this application and which are herein described.

Both ends of the head shaft 20 are simultaneously raised or lowered in amanner to simultaneously apply a uniform tensioning force to each of thechains 23 during the chain adjusting procedure herein described. Thevertical adjusting movement of the head shaft 20 is accomplished bymeans of four hydraulic jacks 35 which are connected in a manner whichwill be described in conjunction with FIG. 4. Each hydraulic jack 35includes a cylinder portion 36 with a reciprocating piston member 37disposed therein for telescopic reciprocal movement with respectthereto. A pair of the hydraulic jacks 35 are used on each side of thetraveling water screen 11 in association with each lifting plate'28. Asillustrated in FIG. 2, a hydraulic jack 35 is placed on each side of thetake-up screw 25 such that the cylinder portions 26 are resting on thebottom member 17. The outer end 38 of each piston member 37 is adaptedto operatively engage the lower surface of the lifting plate 28 upon theoutward movement of the piston members from their respective cylinderportions 36.

Referring now to FIG. 4, there is schematically illustrated a hydraulicsystem designed to supply and control the flow of pressurized fluid tothe hydraulic jacks 35. The hydraulic system includes a reservoir 41which is connected by a suitable fluid transmission line 42 to a pump 43which is equipped with an integral unidirectional valve so as to permitthe flow of fluid in one direction only. The pump 43 may be driven byany suitable means,

4 however, due to the portability of this invention a hand operated pumpis preferred. A fluid transmission line 44 directs the pressurized fluidfrom the pump 43 to a fluid pressure gauge 45, and thence through afluid transmission line 47 to the lines 48 which supply the fluid to thehydraulic jacks 35. The pressure gauge 43 is utilized for indicating theexact pressure applied to the hydraulic jacks 35 which are connected inparallel such that the flow of fluid through the lines 48 and into eachof the cylinder portions 36 causes an equal force to be applied to eachof the piston members 37. In this manner an equal tensioning force issimultaneously applied to both of the chains 23 so as to effect theuniform tensioning of both chains to the same tension value.

Operation of the apparatus is as follows: a pair of the hydraulic jacks35 are positioned on the opposite sides of each take-up screw 25 withthe cylinder portions 36 resting on the bottom member 17. The liftingplates 28 are then vertically adjusted on the take-up screws 25 by meansof the nuts 33 and 34 to the selectable position at which the oppositeends of each lifting plate are in a juxtaposed position with theassociated outer ends 38 of the piston members 37 located therebeneath.Operation of the pump 43 forces fluid through the fluid transmissionlines 44, 47, and 48 so as to drive the piston members 37 outwardly fromtheir associated cylinder portions 36 in a manner to operatively engagethe outer ends 38 with the lower surface of the associated liftingplates 28 so as to effect the elevation of the lifting plates therebyelevating the head shaft 20 and tensioning the chains 23. The head shaft20 is raised until the pressure gauge indicates that the force appliedby the hydraulic jacks 35 has reached the selected value where it haspreviously been determined that the chains 23 are tensioned to properlyengage the foot sprockets, after which the operation of the pump 43 isstopped so as to temporarily support the head shaft at the desiredheight. The capstan nuts 26 are then turned down to abut against the topmember 16, after which they are further turned down until the pressuregauge 45 shows a slight decrease in fluid pressure which indicates thatthe capstan nuts are supporting the head shaft 20. This method ofadjusting the capstan nuts 26 compensates for any distortion of the beam14 as the capstan nuts are adjusted to positively maintain the headshaft 20 at the desired height.

After the head shaft 20 is secured in the selected position, thehydraulic jacks 35 may be removed from the traveling water screen 11.This is accomplished by opening a valve 49 which is interposed in thehydraulic system in a manner to permit the piston members 37 to retractinto their respective cylinder portions 36. The valve 49 has one endcoupled into the fluid transmission line 47 and the other end coupledinto the reservoir 41 by means of a fluid transmission line 51 so thatopening the valve 49 permits the fluid to flow out from the cylinderportions 36 and return to the reservoir. After the piston members 37have been withdrawn into their respective cylinder portions 36, thevalve 49 is closed and the hydraulic jacks 35 may be removed from thetraveling water screen 11 and transported to another traveling waterscreen.

The hydraulic jacks utilized in the system have been illustrated anddescribed as being single acting, and it will be understood that doubleacting hydraulic jacks could also be utilized.

Referring now to FIG. 5 there is illustrated another means of mountingthe invention on a traveling water screen. It will be once againunderstood, of course, that there is an identical chain take-upmechanism disposed on the opposite side of the traveling water screen,and therefore only one such mechanism is illustrated and describedhereinafter. A plate 54 is mounted on the top member 16 of therectangular beam 14 and is structurally reinforced by spaced members 55extending downwardly therefrom and secured to the side members 15 andthe top plate 13. The take-up screw 25 extends through an associatedaperture in the plate 54, and a nut 46 is fitted thereon so as to abutagainst the top surface of a washer 57 which in turn rests on the plate.The nut 56 serves the same function as the capstan nut 26 (FIG. 2)described hereinabove. A horizontally extending rectangular liftingplate 58 having an integrally formed apertured boss projecting from thecenter thereof is supported on the upper end portion of the take-upscrew 25 in a position above the support plate 54, and is secured to thetake-up screw by being clamped between the nuts 61 and 62 which arefitted onto the take-up screw immediately above and below the liftingplate. Rings 63 are welded onto the lower surface of the opposite endportions of the lifting plate 58, and associated rings 64 are welded incorresponding positions on the top surface of the plate 54. The bottomends of the cylinder portions 36 are rested within the rings 64 suchthat upon the actuation of the hydraulic jacks 35 the outer ends 38 ofthe piston members 37 will be elevated into a position within the rings63 so as to engage the lower surface of the lifting plate 58. The rings63 and 64 insure the proper placement and engagement of the hydraulicjacks 35 while simultaneously acting as safety devices to prevent thehorizontal movement of the hydraulic jacks 35 during the chain adjustingprocedure. The operation of the hydraulic system is identical to thatdescribed hereinabove, and the nuts 56 serve to maintain the head shaft20 at the adjusted level after the completion of the adjustingprocedure.

The arrangement and portability of this invention permits the chainadjusting apparatus to be employed for checking and maintaining theproper tension in the chains on several different traveling waterscreens since the hydraulic jacks and associated equipment can bereadily moved between the different locations.

It is to be understood that the form of this invention herewith shownand described is to be taken as a preferred example of the same, andthat various changes in the shape, size, and arrangement of parts may beresorted to without departing from the spirit of the invention or thescope of the subjoined claims.

Having thus described the invention, I claim:

1. In combination with an endless tension member trained for movementaround a pair of substantially parallel shafts, bearing means supportingone of the shafts, guide means supporting the bearing means for movementtoward and away from the other shaft, takeup means associated with thebearing means, and an abutment mounted in a fixed position forengagement by the take-up means so that operation of the latter willeffect the movement of the one shaft to adjust the tension in thetension member, the improvement which comprises:

pressure fluid operated means operatively associated with the one shaftto apply a force thereon so as to urge the movement thereof in adirection to adjust the tension in the tension member and to temporarilyretain the one shaft in the adjusted position during adjustment of thetake-up means to maintain the one shaft in the adjusted position; and

means for indicating the tension in the tension member.

2. The combination described in claim 1 further characterized by thepressure fluid operated means comprising:

a source of pressure fluid;

a chamber supported on the abutment is communication with the source forreceiving pressure fluid therefrom; and

a member reciprocally disposed in the chamber and extending therefromfor telescopic movement relative thereto so as to engage the one shaftand exert a force thereon, the magnitude of the force being a functionof the fluid pressure in the chamber.

3. The combination described in claim 1 wherein the indicating meanscomprises a gauge connected to the pressure fluid operated means formeasuring the pressure of the fluid therein to indicate the tension inthe tension member.

4. The combination described in claim 1 further characterized by thepressure fluid operated means being detachably associated with the oneshaft for ready removal therefrom.

5. In combination with a pair of endless tension members trained formovement around opposite end portions of two substantially parallelshafts, bearings rotatably supporting the opposite ends of one of theshafts and movable toward and away from the other shaft, take-up meansassociated with each bearing and including an abutment mounted in afixed position so that operation of the take-up means will effectmovement of the bearing and the associated end of the one shaft relativeto the other shaft so as to adjust the tension in the tension member atthe associated end of the one shaft, the improvement which comprises:

pressure fluid operated means operatively associated with each bearingfor moving both ends of the one shaft in a direction to simultaneouslyand uniformly adjust the tension in each of the tension members and totemporarily retain the hearings in the adjusted position during theadjustment of the take-up means to maintain the one shaft in theadjusted position; and

means for indicating the tension in the tenison members.

6. The combination as described in claim 5 further characterized by theindicating means comprising a gauge in fluid communication with thepressure fluid operated means for measuring the pressure of the fluidtherein to indicate the tension in the tension members.

7. The combination described in claim 5 further characterized by:

a source of pressure fluid; and

means in fluid communication with the source and each of the pressurefluid operated means for regulating the supply of fluid therebetween soas to supply fluid at a uniform pressure to effect the simultaneousoperation of all of the pressure fluid operated means.

8. The combination described in claim 7 further characterized by fluidpressure relief means being in fluid communication with the pressurefluid operated means for relieving the fluid pressure therein.

References Cited UNITED STATES PATENTS 1,323,818 12/1919 Berry 73143 XR3,004,426 10/1961 Lodyn-ski 73-141 3,082,043 3/1963 Orton 74242.l4 XR3,098,397 7/1963 Schaefer 74242.l4 3,118,315 1/1964 Loosli 74242.l2

RICHARD C. QUEISSER, Primary Examiner.

D CHARLES A. RUEHL, Assistant Examiner.

1. IN COMBINATION WITH AN ENDLESS TENSION MEMBER TRAINED FOR MOVEMENTAROUND A PAIR OF SUBSTANTIALLY PARALLEL SHAFTS, BEARING MEANS SUPPORTINGONE OF THE SHAFTS, GUIDE MEANS SUPPORTING THE BEARING MEANS FOR MOVEMENTTOWARD AND AWAY FROM THE OTHER SHAFT, TAKEUP MEANS ASSOCIATED WITH THEBEARING MEANS, AND AN ABUTMENT MOUNTED IN A FIXED POSITION FORENGAGEMENT BY THE TAKE-UP MEANS SO THAT OPERATION OF THE LATTER WILLEFFECT THE MOVEMENT OF THE ONE SHAFT TO ADJUST THE TENSION IN THETENSION MEMBER, THE IMPROVEMENT WHICH COMPRISES: PRESSURE FLUID OPERATEDMEANS OPERATIVELY ASSOCIATED WITH THE ONE SHAFT TO APPLY A FORCE THEREONSO AS TO URGE THE MOVEMENT THEREOF IN A DIRECTION TO ADJUST THE TENSIONIN THE TENSION MEMBER AND TO TEMPORARILY RETAIN THE ONE SHAFT IN THEADJUSTED POSITION DURING ADJUSTMENT OF THE TAKE-UP MEANS TO MAINTAIN THEONE SHAFT IN THE ADJUSTED POSITION; AND MEANS FOR INDICATING THE TENSIONIN THE TENSION MEMBER.